HIGH-RESOLUTION OPTICAL OBSERVATIONS OF 2 EARLY-TYPE STARS TOWARDS THE HIGH-VELOCITY CLOUD COMPLEX M

High-resolution optical spectra of the early-type stars HD 93521 and BD +38 degrees 2182, which lie only 27 arcmin apart on the sky in the direction of the high-velocity cloud (HVC) Complex M, reveal the presence of weak HVC absorption in the CaK line towards BD +38 degrees 2182, with a velocity of V-LSR = -96.0 +/- 1.5 km s(-1) and an equivalent width W-lambda = 11 +/- 2 m Angstrom. However, the HVC is not detected either in the NaD line for BD +38 degrees 2182 or in the CaK and NaD lines towards HD 93521. These observations, combined with revised stellar distance estimates, imply that the HVC is at a distance from the Galactic plane of 1.8 less than or equal to z less than or equal to 4.6 kpc. The Ca/H abundance in the HVC is found to be at least similar or equal to 2 per cent of the solar value, consistent with the material being returning condensations from a Galactic fountain flow.